Three specific aims will be accomplished by the alterations and renovations proposed. The Comparative Research Center (CRC) will be able to maintain compliance with all animal welfare laws. The CRC will be able to comply with NIH policy and the Guide for the Care and Use of Laboratory Animals. The CRC will be able to meet accreditation requirements of the American Association for Accreditation of Laboratory Animal Care. This proposal is for alteration and renovation of the existing animal resources and equipment. The main facility was renovated in 1974, in a building constructed in 1924. The renovation followed the specifications in the Guide, but was planned to last only five years until new facilities were constructed. It has functioned satisfactorily for eleven years, but is now in need of general renovation. Additional space was assigned to the CRC in 1978 and 1981, but was not renovated. This area is in critical need of renovation, especially the ventilation system. To accomplish the above mentioned goals, the HVAC system will be upgraded to comply with the Guide standards for animals. Dog runs in poor condition will be replaced. Two large rodent rooms will be converted to rooms with individual cubicles for isolation of species and special projects. The cage washing facilities will be enlarged to meet the need for more holding space. Additional service and support functions will be added to meet the Guide standards for facilities of this size, along with necessary general renovation.